Elektor Formant Modular

Hello Kris,

I got my CA3046's today, and finally I'm measuring a
current. It is not exactly what i hoped but it is
getting close. I expect the CA3086's to arrive in a
few days and then I'll compare them.
so here are my  readings:
0v CV : 0.002mA
1V CV : 0.004mA
2V cv : 0.009mA
3V Cv : 0.020mA
4V Cv : 0.052mA


I've been trying to adjust it with P5 But after about
1.5 hrs of adjusting I was going crazy and the results
 above are the best I get.

But as I said, I'll try it again with the CA3086 to
see if that gives me better results.

In the mean time the next problem is already waiting
for me. I took a look at the waveforms with my
oscilloscope and at all 4 points I have the same
waveform which is a sinus with a constant frequency
because changing the input cv doesn't affect it at
all...

Any ideas?

regards, kris
--- Kris Bishop <bishopkris40@...> wrote:


---------------------------------
No problem mate, sounds like this is the main issue
you have. The other 
measurements I had asked you to make, showed that the
comparitor/schmitz 
trigger is getting the correct signal you just need to
charge the capacitor 
so that it will start the oscillations.

If you are having trouble getting parts let me know
and I'll see what I can 
find.

Ca3086: I know a man in Edinburgh bought a lot of
these a few years ago, he 
is a synth designer but he may sell you some if need
be. Ken Macbeth, 
Macbeth studio systems. Not sure if they are for sale,
but he does know 
someone else in china who sells them, just watch your
price! a ca3046 may 
well be just as good.

All the best mate, but let me know how you get on.

Kris


>From: ganesha <goaqihai@...>
>Reply-To: ElektorFormant@yahoogroups.com
>To: ElektorFormant@yahoogroups.com
>Subject: RE: [ElektorFormant] problem with formant
pro vco (new design)
>Date: Tue, 11 Apr 2006 20:54:22 +0100 (BST)
>
>Hi,
>
>Now i'm sure my CA3086 is not ok, If i bend pin 5 to
>measure the  current, I have 0.000mA.
>
>I also unsoldered tr3 to try to measure the current
>between pin3 of ic2, and the place where the
>collectorleg of tr3 should be soldered (this is how
>the German book says the current should be measured)
>and that also gave me 0.000mA.
>I'm going to order a couple of CA3086 and CA3046 ic's
>and see if i can get it fixed with those.
>
>regards,
>kris
>--- Kris Bishop <bishopkris40@...> wrote:
>
> > Ok as I said this thing is strange in ways, the
> > output at IC 6 pin 5, You
> > need to look at the Current not the voltage,
> > although in electronics the two
> > are liknked it would be best that you check the
> > currents before disregarding
> > it.
> >
> > Do you know to test current you have to insert the
> > meter in series. Now
> > Since I had spares I cheated and simply bent pin 5
> > to the side before
> > placing it in the socket, take your time and
you'll
> > be able to do it without
> > damaging devices, mind you I have been involved
with
> > Device manufacture for
> > a few years so I know you can get off with it.
> >
> > Connect one prob to the leg and then with the
other
> > press to the tracjk this
> > should allow you to see the current, you are
looking
> > for it to double for
> > every 1 V change. As for buying more, If they are
> > costing you alot of money
> > then make sure you can return it if it doesn't
work.
> > Also check that the
> > other connections to the device such as ground etc
> > are all ok. CA3046, there
> > is a difference but not sure what it is. I think
> > they were all bought up a
> > little while ago but I suppose you wont see much
of
> > a rise in price. It is
> > worth a go if you want and you can let us know how
> > you get on. Mind don't
> > pay silly prices for the chips, there is always
> > someone out there who will
> > sell for less.
> >
> > Looks like you are getting there though mate.
> >
> > Just for yoour information I use a midi to cv
> > convertor from Synhouse
> > http://www.synhouse.com/midijack.html
> >
> > Works great and it means that if you have synths
> > like mine then you can
> > connect the output of your modular to your synth,
> > control the pitch etc from
> > the synth and treat the output with your synths
> > effects and filters. Since
> > my newest purchase is an Access Virus TI this
works
> > great.
> >
> > Kris
> >
> >
> > >From: ganesha <goaqihai@...>
> > >Reply-To: ElektorFormant@yahoogroups.com
> > >To: ElektorFormant@yahoogroups.com
> > >Subject: RE: [ElektorFormant] problem with
formant
> > pro vco (new design)
> > >Date: Mon, 10 Apr 2006 22:37:58 +0100 (BST)
> > >
> > >Hi All,
> > >OK I did some more measurements:
> > >I think the CA3086 is the problem.
> > >At pin2 and pin5 I have these results:
> > >cv 0V -> IC6 pin2=-0.001V, ic 6 pin5=0.171V
> > >cv 1V -> IC6 pin2=-0.021V, ic 6 pin5=0.171V
> > >cv 2V -> IC6 pin2=-0.041V, ic 6 pin5=0.171V
> > >cv 3V -> IC6 pin2=-0.061V, ic 6 pin5=0.171V
> > >cv 4V -> IC6 pin2=-0.081V, ic 6 pin5=0.171V
> > >
> > >I tested also while turning p8 so the voltage at
> > >collector TR4 was 2.4V but the voltage at pin5
> > >remained the same for the 5 different CV sources.
> > >
> > >So at pin 2 everything seems to be ok, I get
-20mV
> > for
> > >each volt cv I add, But at pin 5 the voltage
> > remains
> > >the same, so I suppose this is the problem?
> > >
> > >Now for IC5 at pin4 I have 5.04V and at pin 5 and
> > pin6
> > >
> > >  I have 0V.
> > >So Should I get another CA3086 or maybe a CA3046?
> > >
> > >regards, Kris
> > >
> > >--- Kris Bishop <bishopkris40@...> wrote:
> > >
> > >
> > >---------------------------------
> > >I sourced my CA's from university, they had been
> > there
> > >for years and used
> > >many times so I had to expect failures, we
students
> > >don;t look after things
> > >that well.
> > >
> > >Concentrate on getting a current in to the
> > comparitor
> > >section, look to get
> > >15uA or there abouts this should kick it off. I
> > would
> > >like you to test the
> > >voltages at IC5, I need to know what pins 4, 5
and
> > 6
> > >read. this is the
> > >section on mine that went wrong. On two VCO's.
> > >
> > >For a first project you are doing well mate.
Catch
> > you
> > >soon
> > >Kris
> > >
> > >
> > > >From: ganesha <goaqihai@...>
> > > >Reply-To: ElektorFormant@yahoogroups.com
> > > >To: ElektorFormant@yahoogroups.com
> > > >Subject: RE: [ElektorFormant] problem with
> > formant
> > >pro vco (new design)
> > > >Date: Sun, 9 Apr 2006 14:49:13 +0100 (BST)
> > > >
> > > >Hello Kris,
> > > >I live in Belgium, My english is ok ( I hope
;-))
> > But
> > > >I don't have much experience with electronics.
> > This
> > >is
> > > >my first project. I managed to build the
> > powersupply
> > > >and the tuningkeyboard (this is the small
> > schematic
> > > >with the 5 switches that produce 0v,1v,2v,3v
> > and4v to
> > > >act as a CV source to tune the VCO. =schematic
> > 3.11
> > >in
> > > >the book) from the book and they both work.
> > > >Btw, the R1 value I changed was for the
> > > >tuningkeyboard, not for the vco. On the vco
I've
> > used
> > > >everything like specified in the componentslist
> > that
> > > >is in the jpg at
> > > >http://www.krinkel.be/formant/formantVCO.JPG
> > > >
> > > >I'll try to do the test what you describe. For
> > the
> > > >other questions:
> > > >
> > > >At the moment I'm only building 1 vco, but I
plan
> > to
> > > >add some as soon as I get this one to work. I
> > also
> > > >want to build the vco of the ems VCS3etc. I
also
> > > >started the VCF but it is not finished yet.
> > > >I bought the pcb + all the components from a
guy
> > in
> > > >germany. When you say only 3 out of 5 CA3086
ic's
> > > >worked, are you sure they got enought voltage?
> > >because
> > > >one of the test in the book is to plug it in
for
> > > >20mins
> > > >to let it warm up, and then at the collector
from
> > tr4
> > > >you have to measure 1.6V to activate the
CA3086.
> > But
> > >I
> > > >read on the internet someone who had to set it
> > to2.4V
> > > >before it worked so this could be what happened
> > with
> > > >the 2 non-working ic's you had. (I'm only
> > guessing
> > > >this offcourse)
> > > >
> > > >The cv comes from the schematic 3.11 in the
book.
> > > >
> > > >I don't have skype yet but I'm sure I can
install
> > it
> > > >by  thursday  so that would be great.
> > > >
> > > >Thanks!
> > > >regards, Kris
> > > >--- Kris Bishop <bishopkris40@...>
wrote:
> > > >
> > > >
> > > >---------------------------------
> > > >I live in Scotland and have the strangest name,
> > > >everyone asks where it is
> > > >from. Can you imagine how strange this is lol
> > > >
> > > >Kris, First how good is your english
> > > >second how good is your understanding of the
> > > >electronics in this synth?
> > > >
> >
>=== message truncated ===
>
>
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